Improvements in and relating to manufacture of electric storage batteries

ABSTRACT

Apparatus for assembling, positioning and securing a battery casing and lid in the manufacture of electric storage batteries comprises a frame and first and second die parts movable relative to the frame and adapted to receive a battery casing or box and a recessed battery lid respectively. The die parts can be caused to retain the box and lid respectively and are movable between a separated position and a position in which the lid is accurately positioned on the box. A heater is movable relative to the frame between an inoperative position and an operative position in which the lid and the box can be moved into contact with the heater. The heater has a portion which, when the lid is moved into contact with the heater, engages an internal peripheral shoulder defined in the recessed battery lid to melt the shoulder, and said portion of the heater is undercut to the rear of the surface of the portion which engages the shoulder so that, when the lid is in contact with the heater, the wall of the lid adjacent the shoulder is not melted.

United States Patent [1 Harris July 17, 1973 [75] Inventor: John Derek Harris, Solihull,

England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England [22] Filed: Jan. 20, 1972 [21] Appl. No.: 219,365

Related US. Application Data [63] Continuation-in-part of Ser. No. 865,921, Oct. 13, 1969, abandoned.

[30] Foreign Application Priority Data July 4, 1968 Great Britain 31,880/68 Jan. 22, 1971 Great Britain 2916/71 [52] US. Cl. 29/204 51 H 01m 35/18 [58] Field of Search 29/204 D, 204 R, 29/203 R, 203 D [56] References Cited UNITED STATES PATENTS 3,544,754 12/1970 Buttke 29/204 D X Primary Examiner-Thomas H. Eager Att0mey.lohn C. Holman et al.

[57] ABSTRACT Apparatus for assembling, positioning and securing a battery casing and lid in the manufacture of electric storage batteries comprises a frame and first and second die parts movable relative to the frame and adapted to receive a battery casing or box and a recessed battery lid respectively. The die parts can be caused to retain the box and lid respectively and are movable between a separated position and a position in which the lid is accurately positioned on the box. A heater is movable relative to the frame between an inoperative position and an operative position in which the lid and the box can be moved into contact with the heater. The heater has a portion which, when the lid is moved into contact with the heater, engages an internal peripheral shoulder defined in the recessed battery lid to melt the shoulder, and said portion of the heater is undercut to the rear of the surface of the portion which engages the shoulder so that, when the lid is in contact with the heater, the wall of the lid adjacent the shoulder is not melted.

7 Claims, 11 Drawing Figures PATENTE JUL 1 7 ma sum 3 0r 7 PATENTEU JUL x mm SHEET It 0F 7 IMPROVEMENTS IN AND RELATING TO MANUFACTURE OF ELECTRIC STORAGE BATTERIES CROSS-REFERENCE TO RELATED APPLICATIONS This invention relates to apparatus for use in the manufacture of electric storage batteries and is a continuation-impart of my application No. 865,921 filed Oct. 13, 1969, now abandoned.

An object of the invention is to provide an improved apparatus for assembling, positioning and securing a battery casing to a lid thereof during manufacture of electric storage batteries.

Apparatus, according to the invention, comprises a frame, first and second die parts movable relative to the frame and adapted to receive a battery box and recessed battery lid respectively, means whereby the die parts can be caused to retain the box and lid respectively, means for moving the die parts between a separated position and a position in which the lid is accurately positioned on the box, and a heater movable relative to the frame between an inoperative position and an operative position in which the lid and the box can be moved into contact with the heater, the heater having a portion which, when the lid is moved into contact with the heater, engages an internal peripheral shoul' der defined in the recessed battery lid to melt the shoulder, and said portion of .the heater being undercut to the rear of the surface of the portion which engages the shoulder so that, when the lid is in contact with the the heater, the wall of the lid adjacent the shoulder is not melted.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, which illustrate the manufacture of a battery according to one example of the invention:

FIG. 1 illustrates a pack of battery plates and separators,

FIG. 2 shows a battery box with all but one of the packs in position,

FIG. 3 is a part sectional view of the battery box illustrating thecompletion of the intercell connections,

FIG. 4 is an inverted plan view of the battery lid,

FIG. 5 is a sectional view along line A-A in FIG. 4,

FIG. 6 is a partly diagrammatic side elevational view illustrating a machine used to connect the lid to the battery box,

FIG. 7 is a part sectional plan view of the heater of the machine shown in FIG. 6,

FIG. 8 is a part sectional side elevational view of the heater shown in FIG. 7,

FIG. 9 is a diagrammatic representation of the operation of the machine shown in FIG. 6, I

FIG. 10 is a sectional view of the battery lid taken along the line 3-8 in FIG. 4 and of part of the heater at one stage during the manufacture of the battery using the machine shown in FIG. 6, and

FIG. 11 is a sectional view of the battery lid and heater at the same stage of manufacture of the battery as shown in FIG. 10 but using a modified form of heater to that shown in FIG. 10.

DESCRIPTION OF PREFERRED INVENTIVE EMBODIMENTS Referring first to FIGS. 1 to 3, a battery box 11 is moulded from polypropylene or other suitable thermoplastic material, the box including partition walls 12 dividing the box into six compartments. Each compartment receives a preformed pack 13 of positive and negative battery plates and separators. The two sets of plates in each of the four packs, which are to be mounted in the central compartments of the box 11 are connected respectively to conductive connecting lugs 15,16 formed with extensions which, in use, extend substantially parallel to the partition walls 12. The extensions on the lugs 15 and 16 are each formed on their surfaces to be presented to the partition walls 12 with an upstanding annular rib I0 and each of the extensions on the lugs 16 is further formed on its surface to be presented to the respective partition wall with an outwardly extending spigot 16a (FIG. 3). The packs which are to be placed in the end compartments, each have one set of plates connected to a lug 15 or 16, and the other sets of plates connected respectively to the terminal posts 17 of the battery.

The partition walls 12 have holes stamped therein, and the arrangement is such that when the packs are positioned in the box 11, each spigot 16a passes through a hole in a respective partition wall and engages the lug 15 on a pack in the adjacent cell, the ribs 10 on each spigot 16a and each lug l5 surrounding the hole in the respective wall. The walls 12 are of course arranged to be sufi'iciently flexible to permit introduction of the packs into the compartments before the spigots 16a enter their respective holes. When all the packs are in position the required intercell connections are completed using a tool 18, as shown in FIG. 3. This tool includes a pair of electrodes 21, 22 which engage corresponding lugs l5, 16 respectively, and simultaneously exert pressure and pass current between the lugs l5, 16 so that the spigot 16a of each lug 16 becomes welded to the respective lug l5, and the hole in the respective partition wall 12 is sealed. When all the intercell connections are made the battery is complete apart from the lid.

The periphery of the open end of the box 1 l, and the free edges of the partition walls 12 lie in the same plane, and adjacent the open end of the box I 1, the box 11 is formed with a peripheral outwardly extending shoulder 23. The outer surface of the wall of the box 11, between the shoulder 23 and the open end of the box 11, tapers inwardly, so that the dimensions of the open end of the box 11 are less than the dimensions of the box adjacent the shoulder 23. Moreover, adjacent its closed end the longer walls of the box I l are formed with respective recesses 24, clamping means (not shown) engaging the recesses 24, in use, and serving to mount the battery in position on a vehicle.

The lid 25 (FIGS. 4 and 5) is also moulded in polypropylene, or other suitable thermo plastic material,

and includes a peripheral wall 26 which extends generally at right angles to the plane of the lid 25, and an internal peripheral shoulder 27 which is engaged by the free end of the wall of the box 11 when the lid 25 is in place closing the box 11. In addition the lid is formed with partition walls 28, which, when the lid is in position on the box 11, engage the free edges of the partition walls 12 of the box 11, the walls 28 of the lid being thicker than the walls 12 of the box 11, to ensure that facial contact occurs between the free edges of the walls 12 and the walls 28. The lid 25 includes six, integral filling tubes 29, each of which has associated therewith a vent passage 31, each tube 29 and respective vent passage 31 being associated with a respective cell of the battery when the lid is in position on the box 11. In use, the lid 25 will have associated therewith, a manifold assembly, which is movable relative to the lid 25 between a first position wherein the vents 31 are open, and a second position wherein the vents 31 are closed. The vents 31 and the tubes 29 open into a common channel 32 in the lid 25, the channel 32 and the manifold assembly (not shown) facilitating simultaneous filling of the six cells of the battery to the desired level with electrolyte. The lid 25 further includes a pair of integral hollow spigots 33 which receive lead inserts for the terminal posts 17 respectively. At its opposite ends respectively the lid 25 includes a pair of integral guide pegs which project from the lower surface of the lid 25 and present to the peripheral wall 26 an inclined surface extending from the shoulder 27 in a direction away from the wall 26. When the lid 25 is positioned on the box 11 the pegs 30 guide the lid into the correct longitudinal position relative to the box 11.

Further guide pegs (not shown) can also be provided on the partition walls 28 of the lid, the further guide pegs being arranged in pairs on each partition wall 28 and serving to guide the walls 28 into engagement with their respective walls 12 when the lid is positioned on the'box 11.

The lid 25 is welded to the box 11, and for this purpose the machine shown in FIG. 6 is used. The machine comprises a frame having a base 34, a pair of pedestals 35, and an arm 36, which extends at right angles to the pedestals 35, and which overlies the base 34. A first die part 37 is slidably mounted on the arm 36, for vertical movement relative to the arm 36. The die part 37 is carried on a pair of guide rods, one of which is shown at 38, and is moved vertically relative to the arm 36 by means of a pneumatic or hydraulic ram 39. A conveyor (not shown) extends over the base 34, and the base 34 includes a platform 41 which is movable vertically, upwardly relative to the base 34, from a position wherein the platform is slightly below the plane of the conveyor. In use, the die part 37 supports a battery lid'25 and the platform 41 carries a battery box 11 which is to have the lid 25 welded thereto. Between the arm 36 and the base 34, the pedestals support a pair of guide ways, one of which is shown at 42, the guide ways 42 extending parallel with the arms 36 and the base 34. Slidably mounted in the guide ways 42 and movable along the guide ways 42 by means of a pneumatic ram (not shown) is a heater assembly 43 (FIGS. 6, 7 and 8). The heater assembly 43 includes a main body 44 carrying rollers 45 by means of which the heater assembly is slidably mounted in the guide ways 42. The body 44 is formed with passages 46 within which electric heating elements are received. Secured to the face of the body 44, which is presented to the base 34, is a plain duralumin plate 47, and secured to the face of the body 44 presented to the arm 36 is a pair of duralumin plates 48a, 48b which are mirror images of one another. The plates 48a, 48b are adjustably secured to the body 44 by means of screws, and are spaced apart by a duralumin packing piece 48c. The plates 48a, 48b and the packing piece 48c define a sub-assembly which on its surface to be presented to the battery lid 25 is substantially the same size as the internal dimensions of the battery lid 25. However, the periphery of the subassembly defined by the plates 48a, 48b and the piece 48c is undercut, as shown at 49, so that the dimensions of the sub-assembly decrease from a maximum value at the surface thereof to be presented to the lid 25 to a minimum value at the surface thereof adjacent the body 44. Moreover, the plates 48a, 48b are provided with holes 51 within which are received the filling tubes 29, the guide pegs 30 and the terminal spigots 33 of the lid 25, when the lid 25 is engaged with the heater assembly 43. Preferably, the duralumin used in the heater assembly has the following composition:

3.5-4% Copper O.40.7% Magnesium 0.4-0.7% Manganese, and up to 0.7% Silicon,

the remainder being aluminium.

Referring now to FIG. 9, in addition to FIGS. 1 to 8, the sequence of operations when interconnecting the box 11 and the lid 25 is as follows:

A series of boxes containing their respective interconnected packs 13, and having respective lids 25 placed thereon are fed onto the conveyor, and are carried by the conveyor between guide rails 53 singly over the platform 41. As a box 11 reaches the platform 41 it engages a stop 52 supported by the pedestals 35, and in so doing operates a micro-switch which starts a cam control system. The cam control system firstly causes the platform 41 to be raised through the moving conveyor, thereby supporting and locating the box 11. Mechanical means (not shown) is now actuated to hold the box 11 firmly in position on the platform 41 for the remainder of the operation. The cam control system then causes the die part 37 to be lowered, until the die part 37 engages the lid 25 which is resting on top of the box 11. When the die part 37 engages the lid 25, movement of the die part 37 and the platform 41 is stopped, and gripping means on the part 37 is actuated so that the lid 25 is gripped by the die part 37. The die part 37 is then returned to its original position so that the lid 25 is lifted away from the box 11, and the platform 41 is lowered to a position a little above the moving conveyor. The heater assembly 43 is now moved along the guide ways 42 so that it occupies a position between the box 11 and the lid 25. The heater assembly 43 is maintained in a heated condition, so that the plates 48a, 48b, the packing piece 480 and the plate 47 are all at 380C. The die part 37 is then lowered, so that the plates 48a, 48b, and the packing piece 48c enter the lid 25 and engage the peripheral shoulder 27 and the free edges of the walls 28 of the lid. One second after the lid 25 has engaged the heater the platform 41 is raised so that the free edge of the wall of the box 11 and the free edges of the partition walls 12 of the box 11 engage the plate 47 of the heater assembly 43. The box 11 and the lid 25 are then maintained in engagement with the heater for a further three seconds, so that the free edges of the wall of the box 11 and the partition walls 12 are heated for three seconds, while the shoulder 27 and the free edges of the partition walls 28 are heated for a total of four seconds. The box 11 and the lid 25 are pressed lightly into contact with the heater assembly 43, and it will be appreciated that since the subassembly defined by the plates 48a, 48b and the packing piece 480 is undercut at 49 (FIG. 10), then the wall 26 of the lid 25, will not be heated.

The die part 37 and the platform 41 are then returned to their previous positions and the heater assembly 43 is retracted from between the lid 25 and the box 11. When the heater assembly 43 is completely retracted, the platform 41 and the die part 37 are moved towards one another to engage the lid with the box 11. The time between the lid 25 and the box 11 leaving contact with the heater assembly 43 and contacting each other is approximately one and a half seconds. The lid is then pressed firmly into contact with the box 11 for four seconds, during which time the areas of the box 11, and the lid 25, which were melted by contact with a heater assembly 43, merge together to seal the lid onto the box. After the lid has been held in contact with the box for four seconds, the lid is released from the die part 37, and the platform 41 is lowered, so that the box 11, together with the lid 25, which is welded thereto are returned to the conveyor, and are replaced by a further box 11, which is to have its respective lid welded to it. In addition the die part 37 is returned to its original position in readiness for a further cycle. The overall cycle of the machine takes twelve seconds.

It is found thatwith battery boxes having partition walls of less than 2 millimetres in thickness and greater than 150 millimetres in length, there is a tendency for the partition walls both during application of pressure between the box and the heater to melt the required areas of the box and during the application of pressure between the box and the lid to seal the lid to the box. To overcome this problem a reduced pressure is used to urge the box into engagement with the heater to effect the initial melting step and in one example the box 11 is urged against the heater assembly 39 at a pressure of 39 p.s.i., whereas the lid 21 is urged against the heater assembly 39 at a pressure of 80 p.s.i., it being appreciated that with a conventional battery box the same pressure,normally 80 p.s.i., is used to urge both the lid and the box against the heater. Further, to effect sealing of the lid to such a battery box, after the initial melting step, the application of pressure between the lid and the box is desirably effected in two stages, that is by initially applying only a low pressure and then increasing the pressure to the desired final value. In one specific example, the lid 21 was pressed against the box 11 at an initial pressure of p.s.i., thepressure then being increased to a final value of 80 p.s.i. and the time of the pressing operation being adjusted accordingly. Further it is found that the provision of the guide pegs 30 on the ends respectively of the lid 25 serve to prevent the free edges of the end walls of the battery box 1l from bending inwardly relative to their respective cell compartments during the application of pressure between the lid and the box. Similarly, if further guide pegs are provided on the partition walls 28 of the lid these serve during the welding operation to retain the free edges of the walls 28 and the walls 12 respectively in face-toface relationship.

As shown in FIG. 1 l, in a modified form of apparatus to that described above, the construction of the heater sub-assembly defined by the plates 48a, 48b and the packing piece 480 is altered. Thus, although the subassembly is undercut to the rear of the surface thereof to be presented to the battery lid 25, the periphery 54 of the sub-assembly defines first and second surfaces 54a, 54b respectively. The first surface 54a of the periphery 54 extends at right angles to the surface of the sub-assembly to be presented to the lid 25 and the second surface 54b extends from the surface 544 to the surface of the sub-assembly adjacent the body 44 and is inclined inwardly with respect to the first peripheral surface 54a so as to define the undercut feature of the sub-assembly. It is, of course, to be appreciated that as in the above example, it is only the shoulder 27 of the lid 25 and the free edges of the walls 28 which are heated by the sub-assembly defined by the plates 48a, 48b and the packing piece 48c when the lid is engaged with the heater. However, by forming the periphery 54 of the sub-assembly in two parts as described greater control can be exerted over the heating of the shoulder 27 than is possible by the use of a heater as described in the first example in which the periphery of the subassembly defined by the plates 48a, 48b and the packing piece 48c is provided with the undercut feature alone.

When the box and the lid are moved away from the heater assembly, any polypropylene from the lid and the box left adhering to the plates 47, 48a, 48b and the packing piece 48c volatilizes leaving the plates in readiness for a further operating cycle. The assembly constituted by the plates 48a, 48b and the packing piece 480, could, of course, be produced as a single part, but in practice the assembly is produced in the three parts so that by replacing the packing piece 480 with alternative duralumin packing pieces of different widths, the assembly constituted by the parts 48a, 48b, 48c can be adjusted to accommodate a range of differently sized battery lids.

Since the outer wall of the free end of the box 11 tapers inwardly, then when the lid 25 is engaged therewith, a wedge shaped gap is defined between the wall of the box 11, and the wall 26 of the lid 25. Thus, when the lid 25 is pressed into engagement with the box 11 toweld the lid 25 to the box 11 molten polypropylene from the box and the lid can flow into the wedge shaped gap as well as inwardly into the compartments of the battery, and it has been found that the provision of the wedge shaped gap enhances the weld produced between the lid and the box. When the lid 25 is pressed into engagement with the box 11, the melted parts of the box 11 and the lid 25 are deformed until the free end of the wall 26 on the lid 25 engages the shoulder 23 on the box 1 l, and thus the wall 26 and the shoulder 23 serve to locate the lid 25 relative to the box 11, and hence contribute to the production of reproducible satisfactory welds.

I claim:

1. Apparatus for use in the manufacture of electric storage batteries, the apparatus comprising a frame, first and second die parts movable relative to the frame and adapted to receive a battery box and a recessed battery lid respectively, means whereby the die parts can be caused to retain the box and lid respectively, means for moving the die parts between a separated position and a position in which the lid is accurately positioned on the box, and a heater movable relative to the frame between an inoperative position and an operative position in which the lid and the box can be moved into contact with the heater, the heater having a portion which, when the lid is moved into contact with the heater, engages an internal peripheral shoulder defined in the recessed battery lid to melt the shoulder, and said portion of the heater being undercut to the rear of the surface of the portion which engages the shoulder so that, when the lid is in contact with the heater, the wall of the lid adjacent the shoulder is not melted.

2. Apparatus as claimed in claim 1 wherein the periphery of said portion of the heater defines a first surface extending substantially at right angles to the surface which engages the shoulder one said portion is inserted into the lid, and a second surface extending from said first surface away from said surface which engages the heater, and being inclined inwardly relative to said first surface so that said portion of the heater is undercut to the rear of said surface which engages the heater.

3. Apparatus as claimed in claim 1 wherein said portion of the heater is in the form of a plate carried by a heater body.

4. Apparatus as claimed in claim 1 wherein said portion of the heater is formed from duralumin.

5. Apparatus as claimed in claim 3 wherein said plate is formed in several pieces which are detachably seond portion is constituted by a duralumin member. 

1. Apparatus for use in the manufacture of electric storage batteries, the apparatus comprising a frame, first and second die parts movable relative to the frame and adapted to receive a battery box and a recessed battery lid respectively, means whereby the die parts can be caused to retain the box and lid respectively, means for moving the die parts between a separated position and a position in which the lid is accurately positioned on the box, and a heater movable relative to the frame between an inoperative position and an operative position in which the lid and the box can be moved into contact with the heater, the heater having a portion which, when the lid is moved into contact with the heater, engages an internal peripheral shoulder defined in the recessed battery lid to melt the shoulder, and said portion of the heater being undercut to the rear of the surface of the portion which engages the shoulder so that, when the lid is in contact with the heater, the wall of the lid adjacent the shoulder is not melted.
 2. Apparatus as claimed in claim 1 wherein the periphery of said portion of the heater defines a first surface extending substantially at right angles to the surface which engages the shoulder one said portion is inserted into the lid, and a second surface extending from said first surface away from said surface which engages the heater, and being inclined inwardly relative to said first surface so that said portion of the heater is undercut to the rear of said surface which engages the heater.
 3. Apparatus as claimed in claim 1 wherein said portion of the heater is in the form of a plate carried by a heater body.
 4. Apparatus as claimed in claim 1 wherein said portion of the heater is formed from duralumin.
 5. Apparatus as claimed in claim 3 wherein said plate is formed in several pieces which are detachably secured to the body, at least one of the pieces being replaceable with a further piece of different dimensions so as to alter the overall dimensions of the plate.
 6. Apparatus as claimed in claim 1 wherein the heater includes a second portion of the side of the heater remote from said first mentioned portion, said second portion being engageable with the periphery of the open end of a battery box to melt the surface of the periphery of said open end.
 7. Apparatus as claimed in claim 6 wherein said second portion is constituted by a duralumin member. 